一辆长30 m的大型平板车,在匀速通过70 m长的大桥时,所用时间是10 s,它以同样的速度通过另一座桥,用了20 s的时间,那么这座桥的长度是 ( )
A:140 m
B:200 m
C:170 m
D:230 m
We have made a survey among 1,000 students from a middle school about their favorite food. students like fruits according to the form.
Kind of food
Chocolate
Banana
Cookie
Apple
Percentage(百分比)
Of the students
20%
30%
15%
?
下列叙述中,前者是化学性质,后者是该项性质表现出来的化学变化的是( )
下列句子中加线的词语使用恰当的一项是( )